Hello forums, in the context of a little DIY-project I am planning to build a rudimentary fluorometer, which is actually doing nothing but checking whether an amout of protein is fluorescing or not, and roughly measuring its intensity. A highpower LED is used to excite the protein to the fluorescent state, while a phototransistor (specially sensitive to the fluorescent spectrum) starts measuring a short time after the LED has been turned off. The live time of fluorescence is in the region of a few nano seconds. For example a nanosecond pulsed measurement should (tightly) be able to solve the problem. Do you know circuitries which can handle this measurement cycle?